To reinforce rubber tires cord is frequently used; the cord can run from one bear ring to the other crosswise to the torus of the tire and can be anchored to these bead rings. Also a belt can be positioned along the circumference. Bead rings, radial reinforcements and belt are held in place by vulcanized rubber, the tire building process involving first the glueing of non-vulcanized elements to each other, and then vulcanizing of them so as to form a unit. With rubber tires, therefore, the positioning of the reinforcement presents no difficulty.
In tire made from castable or sprayable elastomers reinforcements as known from rubber tires can also be used. Unlike tire building of rubber tires, however, positioning of the reinforcements in these cases is difficult, because the reinforcement must, within the hollow space of the mold, be fixed at a given distance from the core of the mold. It has, for instance, been suggested that the core of the mold be provided with ribs, or that the radial reinforcement itself can be provided with projections. The production of such tires is relatively complicated and there is also the danger that the tire will be non-homogenous in places.
In some mechanized field work it is important that the tires of the tractors exert as little specific pressure on the ground as possible, so as to avoid damage to the ground. Up to now, to achieve this, rubber tires with the known radial reinforcement anchored to the beadrings have been used; however the width of the tires was substantially increased, in most cases to nearly double the standard width, and also air pressure was considerably reduced. Although this results in a lower specific ground pressure, the reinforcements of the side walls reach to the anchoring at the bead rings and the side walls still remain stiff which adversely influences the ground pressure.